The use of digital photography for the definition of coastal biotopes in Azores.

Copyright © Springer Science+Business Media B.V. 2007.Sampling benthic communities usually requires intensive field and lab work which is generally performed by skilled staff. In algal dominated communities, like those on the shores of the Azores, biotope characterization studies focused on the more conspicuous algae categories, thus reducing the skills required for species identification. The present study compares in situ quadrat quantifications done by a skilled reader, with computer based quadrat quantifications using digital photographic records of the same areas read in situ, accomplished by skilled and non-skilled readers. The study was conducted inter- and subtidally at various shore heights/depths. Quantification of algal coverage, both in situ and computer based, used the point to point method with quadrats of 0.25 m × 0.25 m for the intertidal, and 0.50 m × 0.50 m for the subtidal surveys, both subdivided into 36 intersection points. Significant differences were found between in situ readings and computer based readings of photographic records conducted both by experienced and inexperienced readers. Biotopes identified using in situ data and image based data differ both for the subtidal and intertidal